Obviously as an optometrist I have played a role in the management of many diabetic patients over the years.
If you think this is just going to be another article on diabetic retinopathy, think again.
Patients with significant diabetic retinopathy are usually straightforward to manage, especially if you have a retinal camera. If you take some photos and show them the haemorrhages in their eye, it’s usually not all that difficult to get them to attend their appointment/s with an ophthalmologist and undergo treatment.
The cases that I have found difficult to manage are the ones where the blood sugar levels are inconsistent or far too high, or where a patient is unaware that they have diabetes.
Today I would like to discuss the back story to 3 different cases that have stuck in my mind.
Case 1 – undiagnosed diabetes with a significant myopic shift
The first case is of a patient who had purchased glasses from the practice where I was working about 6 months previously. Let’s say in February. I come into the story where she presented in August of the same year saying that her distance vision was blurred and that her reading glasses felt too strong.
When I looked at her spectacle prescription from February, I could see that it was:
R: +0.50DS (6/6)
L: +0.50DS (6/6)
Near addition +2.00D
So previously she had good distance vision, and reading glasses with a +2.50D prescription. Pretty standard for a 48 year old.
When I did a spectacle prescription check in August, it was:
R: -2.25DS (6/6)
L: -2.50DS (6/6)
Near addition +2.25D
So based on the new assessment, she would need distance glasses and would be able to read unaided.
Obviously she’d had a myopic shift of approximately -3.00D in a six month period and it was time for me to consider possible causes.
Given the nature of the myopic shift, I suspected that she had developed cataracts or was diabetic. However, given that the acuity was still 6/6 in each eye, I figured that I would most likely rule out cataracts on slit lamp examination, as cataracts which cause such a myopic shift would be likely to cause an acuity more like 6/12.
The slit lamp examination, posterior segment examination and intraocular pressure check all indicated healthy eyes (but not necessarily a healthy patient).
After discussion with the patient involving the fact that I suspected her blood sugar levels were high, I recommended that she see her GP and have a fasting blood sugar level test done, she did put up some protest saying that her blood sugar levels had been normal in the previous year.
After trying to reiterate the fact that this was potentially serious and needed to be ruled out as a possible cause of the vision change, the patient agreed to go to the GP. I sent a letter to the GP, and told the patient I would call her in about 2 weeks’ time to see how she was getting along.
Might I say that it was a very interesting phone call a fortnight later. The patient said that her GP was reluctant to order a fasting blood sugar as she was “in the healthy weight range” and didn’t have any symptoms of diabetes.
However, since I’d sent a letter specifically asking for a fasting blood sugar level test to be done, they thought they would do it “just in case.”
When it was found that the fasting blood sugar level was 48mmol/L, high enough that many people would have been unconscious (Diabetes Australia says that normal is 4 to 6 mmol/L), the patient received immediate medical care.
In that 2 week period, she had noticed a dramatic improvement to her distance vision, and noticed that although her existing reading glasses weren’t exactly right, her near vision was better with them than without them.
On the phone, I let the patient know that her vision would most likely return to normal in the coming weeks, and that I would be happy to check her vision again at any stage. I did mention that if she needed to update her glasses for any reason, that her blood sugar levels would need to be under 10 for at least a month in order for the results of the spectacle prescription check to be accurate.
A few weeks later the patient presented as she had broken her reading glasses (beyond repair) and wanted new ones. Her blood sugar levels had been fluctuating from about 8 to 16.
It was quite obvious at the beginning of the consultation that the patient was not overly excited to see me, was generally in poor spirits and, by my estimate, weighed about 10kg more than when I’d seen her a few weeks previously. On questioning about whether, on reflection, she’d had any symptoms in the lead up to her diagnosis of diabetes, she said that she had been enjoying it as the weight had just been dropping off without her having to do anything out of her normal routine.
I let her know that I could do a spectacle prescription check, but that the results were going to be unreliable as her blood sugar levels hadn’t yet stabilized. The refraction result was:
R: -0.50DS (6/6)
L: -0.50DS (6/6)
Near addition +2.00D
I suggested that a pair of +1.50 magnifiers from the chemist would be a more cost effective alternative for the next few weeks, and that we should recheck again in about 2 months’ time, as long as her blood sugar levels were consistently under 10 for at least a month at the time of the next check.
However, the patient had been to the chemist and didn’t like any of the styles of the frames of the readymades, and insisted on having glasses made up in our practice.
Obviously I let her know that it would be her choice to do so, and that she would need to expect to have to pay for new lenses again in the coming weeks or months as her vision would continue to change during this time. At this stage I knew it was against my better judgement to dispense spectacles, but thought it was better to do so that she would at least have something to wear while reading instead of nothing. I figured that a pair of +1.50s would be a decent compromise if her vision fluctuated a little bit either plus or minus.
The plot thickened when she came back to collect the glasses two weeks later and found that the reading distance was too close. A recheck on this day gave a prescription of:
R: -1.25DS (6/6)
L: -1.25DS (6/6)
Near addition +2.00D
By this stage the patient was most annoyed with me for not getting her glasses right. I made a genuine offer to remake the spectacles with the new prescription, and said that I would keep the +1.50 lenses in the practice as it was likely that they would be required again in the coming weeks or months.
The patient made a comment with words to the effect of me being incompetent and asked for a refund. I said that I would be happy to give her a refund as yes, she was correct, I had been unable to supply her with suitable glasses, but that until her blood sugar levels stabilized, she would have a similar experience if she went elsewhere. I told her that I felt she was better off to stick with me as I had the whole picture on what was happening with her eyes.
She again said that she would like a refund, which I promptly organised. She left the practice, never to be seen again.
This is where I stated to more seriously reflect on what had happened. Here I was thinking that she should have been grateful to me for saving her health, if not her life. What if she’d passed out while driving if her blood sugar levels had gone a bit higher? Could I have done anything differently to manage the situation better? It seemed to me that the patient was in denial about the whole thing, but am I really placed to do anything about this during an optometric consultation?
I would love to have some comments about anything else I could have done, as obviously I would have liked to keep this patient under my care.
Case 2 – diagnosed diabetes with fluctuating blood sugar levels
A continuing patient who I’d seen a couple of times previously presented for a spectacle prescription check as she felt that there had been a change to her vision. She was a known diabetic, and said that her blood sugar levels had been fluctuating and so the GP was in the process of changing her diabetes medication.
As you might expect, there was a bilateral myopic shift of approximately -1.25D. She too wanted new glasses made up. But not because she’d broken her old ones. She thought it was time for a change and wanted a new look.
This was a couple of years after my encounter with the patient from Case 1. So here I thought I would be doing “the right thing” by explaining to the patient that her fluctuating vision was temporary, and that if we checked it again in about 6-8 weeks’ time, after everything had settled down. I let her know that it wouldn’t be in her best interests to do anything with her glasses for the time being.
I attempted reiterate that I was actually doing my best to give her what she wanted, but that it was just that she would need to wait a little longer than she wanted in order to get it. I encouraged her to book an appointment for about 7 weeks’ time, and was a little surprised when she actually did, given the tone in her voice earlier in the conversation.
However, it was hardly a surprise when 7 weeks later, she didn’t show up for her appointment.
So now we have two cases where trying to do the right thing can seem like doing the wrong thing when it comes to the management of patients with diabetes. Let’s move on to case 3.
Case 3 – undiagnosed diabetes with an unstable refraction
Although this case bothered me personally, it did have a happy ending.
A man in his 60s presented for a second opinion for glasses as he had recently had spectacles made up and then remade in a practice elsewhere.
Assessment of the refraction made me suspect either of three things:
- The other optometrist simply “got it wrong”
- The patient was developing cataracts
- The patient was diabetic
After the refraction I let the patient know that we needed to look at which of the 3 causes was most likely to be correct. Slit lamp examination ruled out cataracts, so I recommended that before we go any further, he see his GP for a fasting blood glucose check.
Sure enough, the blood test results revealed diabetes. The patient worked with his GP to get his blood sugar levels back into the normal range, and presented a couple of months later, after his blood sugar levels had been consistently under 10 for over a month. We were able to get his glasses right.
So what bothers me about this situation? The fact that the patient said that his previous optometrist had been “John” (not his real name) from “a certain practice.” It turned out that “John” was a recent graduate who I had supervised a couple of years before in a clinical setting when he was an optometry student.
I do recall John as being a bright student who was always willing to learn, and felt that even though I had attempted to get all the optometry students I’d supervised to look at the bigger picture and to question things when something wasn’t adding up, somewhere along the line I had failed him and the training system had failed him.
The case involving this patient was a personal “win” for me as I knew I’d nailed it. It was also a nice ego boost when the patient then sent his wife in for an eye test as well, with his wife having heard all about how wonderful I was. It was also a “win” for the patient, as he was able to get the care he needed. So although it wasn’t a “win” for that optometry graduate in that instance, I hope this can turn into a win for this generation of young optometrists and their patients as it will ensure that they question unexplained myopic shifts and/or inconsistent refractions.
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